ns172 design requirements for cable jointing pits and vaults · for works involving significant...

NW000-S0012 UNCONTROLLED IF PRINTED of 25

Network Standard

NETWORK

Document No Amendment No Approved By Approval Date Review Date

: : : : :

NW000-S0012 4 Manager – T & DME 17/07/2019 17/07/2022

Supersedes Network Standard (NETWORK) NW000-S0012 Amendment No.3

NW000-S0012 NS172 DESIGN REQUIREMENTS FOR CABLE JOINTING PITS AND VAULTS

NS172 Design Requirements for Cable Jointing Pits and Vaults Amendment No 4


ISSUE

For issue to all Ausgrid and Accredited Service Providers’ staff involved with the design and construction of power cable jointing pits and vaults, and is for reference by field, technical and engineering staff.

Ausgrid maintains a copy of this and other Network Standards together with updates and amendments on www.ausgrid.com.au.

Where this standard is issued as a controlled document replacing an earlier edition, remove and destroy the superseded document

DISCLAIMER

As Ausgrid’s standards are subject to ongoing review, the information contained in this document may be amended by Ausgrid at any time. It is possible that conflict may exist between standard documents. In this event, the most recent standard shall prevail.

This document has been developed using information available from field and other sources and is suitable for most situations encountered in Ausgrid. Particular conditions, projects or localities may require special or different practices. It is the responsibility of the local manager, supervisor, assured quality contractor and the individuals involved to make sure that a safe system of work is employed and that statutory requirements are met.

Ausgrid disclaims any and all liability to any person or persons for any procedure, process or any other thing done or not done, as a result of this Standard.

All design work, and the associated supply of materials and equipment, must be undertaken in accordance with and consideration of relevant legislative and regulatory requirements, latest revision of Ausgrid’s Network Standards and specifications and Australian Standards. Designs submitted shall be declared as fit for purpose. Where the designer wishes to include a variation to a network standard or an alternative material or equipment to that currently approved the designer must obtain authorisation from the Network Standard owner before incorporating a variation to a Network Standard in a design.

External designers including those authorised as Accredited Service Providers will seek approval through the approved process as outlined in NS181 Approval of Materials and Equipment and Network Standard Variations. Seeking approval will ensure Network Standards are appropriately updated and that a consistent interpretation of the legislative framework is employed.

Notes: 1. Compliance with this Network Standard does not automatically satisfy the requirements of a Designer Safety Report. The designer must comply with the provisions of the Workplace Health and Safety Regulation 2017 (NSW - Part 6.2 Duties of designer of structure and person who commissions construction work) which requires the designer to provide a written safety report to the person who commissioned the design. This report must be provided to Ausgrid in all instances, including where the design was commissioned by or on behalf of a person who proposes to connect premises to Ausgrid’s network, and will form part of the Designer Safety Report which must also be presented to Ausgrid. Further information is provided in Network Standard (NS) 212 Integrated Support Requirements for Ausgrid Network Assets.

2. Where the procedural requirements of this document conflict with contestable project procedures, the contestable project procedures shall take precedent for the whole project or part thereof which is classified as contestable. Any external contact with Ausgrid for contestable works projects is to be made via the Ausgrid officer responsible for facilitating the contestable project. The Contestable Ausgrid officer will liaise with Ausgrid internal departments and specialists as necessary to fulfil the requirements of this standard. All other technical aspects of this document which are not procedural in nature shall apply to contestable works projects.

INTERPRETATION

In the event that any user of this Standard considers that any of its provisions is uncertain, ambiguous or otherwise in need of interpretation, the user should request Ausgrid to clarify the provision. Ausgrid’s interpretation shall then apply as though it was included in the Standard, and is final and binding. No correspondence will be entered into with any person disputing the meaning of the provision published in the Standard or the accuracy of Ausgrid’s interpretation.

KEYPOINTS

This standard has a summary of content labelled “KEYPOINTS FOR THIS STANDARD”. The inclusion or omission of items in this summary does not signify any specific importance or criticality to the items described. It is meant to simply provide the reader with a quick assessment of some of the major issues addressed by the standard. To fully appreciate the content and the requirements of the standard it must be read in its entirety.

AMENDMENTS TO THIS STANDARD

Where there are changes to this standard from the previously approved version, any previous shading is removed and the newly affected paragraphs are shaded with a grey background. Where the document changes exceed 25% of the document content, any grey background in the document is to be removed and the following words should be shown below the title block on the right hand side of the page in bold and italic, for example, Supersedes – document details (for example, “Supersedes Document Type (Category) Document No. Amendment No.”).

http://www.ausgrid.com.au/

KEY POINTS OF THIS STANDARD


Design Identification, Signage, Inspection, and Certification Scope and Risks Addressed

Tools and Forms Annexure A – Sample NS Compliance

Checklist

This Network Standard describes the minimum design requirements for cable jointing pits and vaults for use with power cables and pilots. For communications pits, refer to

NS204.2.1 Communications Pits – Specifications and Installation Guidelines.

This standard does not cover construction requirements or other issues relating to construction activities.

For works involving significant modifications to existing pits, the modified pit design shall comply with the requirements of this Network Standard to the extent that is reasonably practicable.

All materials used must be free from Asbestos.

Confined space training and procedures apply.

Where to for more information? Sections 1 - 5

The following major design requirements are included:

Design options Design loads Dimensions Access Confined space issues Items to be included in pits: Access covers Ladder Pulling eyes Cable supports Embedded earthing Drawings

This standard also includes requirements in relation to:

Pit identification and signage Inspections during construction Certification of designers and pit

design Requirements for Certificate of

Practical Completion following final inspection.

Tools and Forms Not applicable

Where to for more information? Section 6

Where to for more information? Section 7 - 10



Network Standard NS172

Design Requirements for Cable Jointing Pits and Vaults

Contents

1.0 PURPOSE ............................................................................................................................................. 6

2.0 SCOPE .................................................................................................................................................. 6

3.0 RELATED DOCUMENTS ...................................................................................................................... 6 3.1 General....................................................................................................................................... 6 3.2 Ausgrid documents .................................................................................................................... 6 3.3 Other standards and documents ................................................................................................ 7 3.4 Acts and regulations ................................................................................................................... 7

4.0 DEFINITIONS ........................................................................................................................................ 7

5.0 ASBESTOS ............................................................................................................................................ 8

6.0 DESIGN REQUIREMENTS ................................................................................................................... 8 6.1 General....................................................................................................................................... 8 6.2 Design options ........................................................................................................................... 8 6.3 Design loads .............................................................................................................................. 9 6.4 Pit dimensions .......................................................................................................................... 10

6.4.1 General ......................................................................................................................... 10 6.4.2 Minimum size ............................................................................................................... 10 6.4.3 Cable working constraints ............................................................................................ 10 6.4.4 Columns ....................................................................................................................... 11 6.4.5 Access and egress ....................................................................................................... 12 6.4.6 Multi-part accesses ...................................................................................................... 12 6.4.7 Egress distance vs internal height ............................................................................... 12 6.4.8 Restricted access ......................................................................................................... 13

6.5 Confined space requirements .................................................................................................. 14 6.6 Standard items ......................................................................................................................... 14

6.6.1 General ......................................................................................................................... 14 6.6.2 Access covers .............................................................................................................. 15 6.6.3 Ladders ........................................................................................................................ 16 6.6.4 Pulling eyes .................................................................................................................. 16 6.6.5 Cable supports ............................................................................................................. 16 6.6.6 Embedded earthing ...................................................................................................... 17

6.7 Design drawings ....................................................................................................................... 17

7.0 IDENTIFICATION AND SIGNAGE ...................................................................................................... 18 7.1 Summary .................................................................................................................................. 18 7.2 Typical signs ............................................................................................................................ 19

8.0 INSPECTIONS ..................................................................................................................................... 21 8.1 General..................................................................................................................................... 21 8.2 Ground conditions .................................................................................................................... 21 8.3 Reinforcement inspections ....................................................................................................... 21 8.4 Concrete pours ......................................................................................................................... 21 8.5 Final inspection ........................................................................................................................ 21

9.0 CERTIFICATION ................................................................................................................................. 21



10.0 COMPLETION ..................................................................................................................................... 22

11.0 RECORDKEEPING ............................................................................................................................. 23

12.0 AUTHORITIES AND RESPONSIBILITIES .......................................................................................... 23

13.0 DOCUMENT CONTROL...................................................................................................................... 23

ANNEXURE A – SAMPLE COMPLIANCE CHECKLIST ................................................................................ 24



1.0 PURPOSE This Network Standard describes the minimum design requirements for cable jointing pits and vaults for use with power cables and pilots.

For pits exclusively for use with optical fibre pilot cables, refer to NS204.2.1 Communications Pits - Specifications and Installation Guidelines.

2.0 SCOPE This Network Standard describes the minimum design requirements for new jointing pits and vaults for use with power cables and pilots. It does not cover construction requirements, authority approvals, safety or environmental requirements relating to construction. Normal industry practices apply in addition to any Ausgrid design requirements detailed herein.

For works involving significant modifications to existing pits that would have been originally constructed to a previous standard, the modified pit design shall comply with the requirements of this Network Standard to the extent that is reasonably practicable.

3.0 RELATED DOCUMENTS 3.1 General

All work covered in this document shall conform to all relevant Legislation, Standards, Codes of Practice and Network Standards. Current Network Standards are available on Ausgrid’s Internet site at www.ausgrid.com.au.

3.2 Ausgrid documents • Company Form (Governance) - Network Technical Document Endorsement and Approval • Company Procedure (Governance) - Network Technical Document Endorsement and

Approval • Company Procedure (Network) – Network Standards Compliance • Company Procedure (Network) - Production / Review of Engineering Technical Documents

within BMS • Electrical Safety Rules • Electricity Network Safety Management System Manual • NEG-SM04.24.06 Inspection and Test Quality Procedure • NS100 Field Recording of Network Assets • NS104 Specification for Electrical Network Project Design Plans • NS130 Specification for Laying of Underground Cables Up to 11 kV • NS148 Overhead Line Support, Street Light Column, Pit and Pillar Numbering • NS149 Drawing Content for Chamber Type Substations, Control Points, Cable Risers and

Ductlines • NS156 Working Near or Around Underground Cables • NS168 Specification for the Design and Construction of 33kV, 66kV and 132kV Underground

Cables • NS174 Environmental Procedures • NS181 Approval of Materials and Equipment and Network Standard Variations • NS203 Telecommunications Network Master Policy Document • NS204.2.1 Communications Pits - Specifications and Installation Guidelines • NS212 Integrated Support Requirements for Ausgrid Network Assets • NS260 Sub-Transmission Feeder Earthing Design



• NS261 Requirement for Design Compliance Framework for Network Standards Refer to NS104 Specification for Electrical Network Project Design Plans for a more comprehensive list of available Network Standards.

3.3 Other standards and documents • ENA Doc 001-2008 National Electricity Network Safety Code • AS 5577 – 2013 Electricity Network Safety Management Systems • AS/NZS 1170 Structural design actions • AS/NZS 1891.4 Industrial fall-arrest systems and devices - Selection, use and maintenance • AS 1100 series – Technical drawing • AS 1319 Safety signs for the occupational environment • AS 1657 Fixed platforms, walkways, stairways and ladders – Design, construction and

installation • AS 2865 Confined Spaces • AS 3600 Concrete Structures • AS 3610 Formwork for concrete • AS 3850.1 Prefabricated concrete elements, Part 1: General requirements • AS 3996 Access covers and grates • AS 4586 Slip resistance classification of new pedestrian surface materials • AS 5100 Bridge Design Set

3.4 Acts and regulations • Electricity Supply (General) Regulation 2014 (NSW) • Electricity Supply (Safety and Network Management) Regulation 2014 • Work Health and Safety Act 2011 (NSW) • Work Health and Safety Regulation 2017

4.0 DEFINITIONS Accredited Service Provider (ASP)

An individual or entity accredited by the NSW Department of Planning and Environment, Energy, Water and Portfolio Strategy Division, in accordance with the Electricity Supply (Safety and Network Management) Regulation 2014 (NSW).

Business Management System (BMS)

Ausgrid’s internal integrated policy and procedure framework that contains the approved version of documents.

Compliance Officer

Ausgrid officer responsible for dealings with parties involved in construction of Ausgrid network assets. For contestable works this would normally be the ASP Compliance Officer.

Document control

Ausgrid employees who work with printed copies of document must check the BMS regularly to monitor version control. Documents are considered “UNCONTROLLED IF PRINTED”, as indicated in the footer.

Embedded Earthing

The steel reinforcing installed in the concrete slab and walls is welded together to form a conductive mesh and provided with a connection facility to allow it to be bonded to the local earthing system.

Network Standard

A document, including Network Planning Standards, that describes the minimum company requirements for planning, design, construction, maintenance, technical specification, environmental, property and metering activities on the distribution and transmission network. These documents are stored in the Network Category of the BMS repository.



Inspection and Test Plan (ITP)

An Inspection and Test Plan is document that records all inspection and testing requirements relevant to a specific process or element of work. Refer to NEG- SM04.24.06 Inspection and Test Quality Procedure.

Pits Underground enclosures usually constructed of brick or concrete in which cables are jointed. Used for the 11kV and low voltage distribution network

Project Officer Ausgrid officer responsible for coordinating parties involved in the design of Ausgrid network assets. For contestable works this would normally be the Major Connections Project Officer.

Review date The review date displayed in the header of the document is the future date for review of a document. The default period is three years from the date of approval however a review may be mandated at any time where a need is identified. Potential needs for a review include changes in legislation, organisational changes, restructures, occurrence of an incident or changes in technology or work practice and/or identification of efficiency improvements.

Vaults Underground enclosures constructed of brick or concrete in which cables are jointed. Vaults are enterable by personnel via a hatch or door. Used for the transmission and sub-transmission network.

5.0 ASBESTOS All materials and equipment used for construction of Ausgrid’s assets are to be free from Asbestos and or Asbestos related products.

Suppliers are expected to comply with Work Health and Safety Act 2011 (WHS) together with the WHS Regulation 2017 and confirm in writing that all products supplied to Ausgrid contain no Asbestos related materials.

6.0 DESIGN REQUIREMENTS 6.1 General

The pit shall be designed to all the relevant Australian Standards including those listed in Section 3.0 References.

Note: This document uses ‘pits’ to denote ‘pits or vaults’ when dealing with general issues that apply to both pits and vaults.

6.2 Design options Acceptable design options for pits are:

a. Pre-cast reinforced concrete. b. Constructed in-situ reinforced concrete blockwork. c. Cast in-situ reinforced concrete. d. Brickwork.

The geographical location shall be considered when determining the design option to be used, as indicated below:

Brickwork pits shall only be used in areas of rock and where the area around the pit is backfilled with a sand/cement mix.

In tidal areas or where a pit is below the water table:

• Only pre-cast or cast in-situ reinforced concrete shall be used.

• Suitable 50MPa reinforced concrete shall be used.

• Hydrophilic water stops shall be used to seal construction joints.



• An additive shall be used in the concrete to give it non-absorptive properties - products such as Xypex or 3CC (by Cementaid) or an approved equivalent are acceptable and shall be used in accordance with the manufacturer's recommendations.

• Suitable hydraulic seals shall be used for all conduit entries into the pit, this should seal both the inside and outside (embedded) conduit surfaces to restrict the ingress of water.

In Acid Sulfate Soils (ASS):

• Only pre-cast or cast in-situ reinforced concrete shall be used.

• Suitable 50MPa reinforced concrete using Sulfate Resisting (SR) cement shall be used.

• Soil disposal shall be to an approved disposal facility.

Alternative design options and materials for pits may be approved by Ausgrid via a NS181 Network Standard Variation Request, provided that the following risk factors are considered and adequately mitigated:

• Design life and durability impacts at the geographical location.

• Fire resistance for a credible pit fire.

• Cross-bracing requirements where a roof slab may need to be removed in future.

• Conduit penetration constraints, eg minimum distance from wall/floor edges, maximum allowable % of wall area.

• Ladders/step-bolts attachment method & potential for corrosion.

• Pulling eye constraints, eg limited load rating.

• Wall attachment constraints.

• Design standards.

• Need & cost for original supplier design input for future pit modifications.

• Water ingress and control options.

• End of life - recycling or abandonment in-situ.

6.3 Design loads The pit and access covers shall be designed for a service life of 50 years. If specified by Ausgrid the service life of the pit shall be increased to 100 years at specific locations, and the corresponding durability requirements will be increased to comply with AS 5100.

The pit and any temporary road cover for use during construction shall be designed to carry the design loads in Table 1:

Table 1 – Design loads

Location Design loads

Road Loads and load factors required by AS5100 (dead load, superimposed dead load, soil/groundwater load etc), including SM1600 and HLP320 road traffic loads.

Footpath As road design loads above, but with no dynamic load allowance applied.

The pit shall also be designed for any special conditions unique to its location such as:

• Crane loads,

• Loading from neighbouring building foundations,



• Design for support of other services in or near the pit for both construction and final situations to meet the relevant Authority requirements,

• Buoyancy forces if there is the potential for a high water table, or where the pit is in a tidal area.

The ground adjacent to the pit accesses shall be capable of withstanding construction and service loads applied by vehicles and any cranes required for lifting. Sufficient space to position and operate a crane shall be provided where required.

Pit walls & floors that include pulling eyes shall be designed to cater for the rated working load of the pulling eyes at any location on the wall or floor.

The pit design drawings shall include suitable notation on the following construction related aspects:

• Shoring requirements - evidence of inspection and design of shoring by an approved geotechnical engineer shall be provided by the Contractor to the Compliance Officer.

• Concrete curing requirements.

• Concrete strength and age requirements before backfilling around the pit and before traffic may be carried on adjacent ground.

6.4 Pit dimensions 6.4.1 General The final size of the pit is to be approved by the Project Officer.

It is recognised that other underground services are often present and that these will often govern the final size and shape of the pit.

6.4.2 Minimum size The minimum internal plan dimensions for pits shall be as per Table 2.

Table 2 – Minimum Pit Size

Pit Type Size

HV pits where cable bends need to be accommodated within the pit 5m x 4m

HV narrow pits where no significant cable bending is needed 5.7m x 2m

LV pits 2m x 2m

A pit that uses a fixed roof shall have minimum 2m internal height, wherever this is reasonably practicable. Lower internal heights shall be assessed in accordance with Table 4.

The depth of pits having a fully removable roof (including multi-part covers, precast concrete roof lids etc.) may be less than 2m. The depth of these pits shall be minimised but is to be compatible with the depth of the cables entering the pit.

6.4.3 Cable working constraints In addition to the minimum pit sizes specified in Table 2, the pits shall cater for the following cable working constraints to allow for the nominal minimum internal cable bending radii during installation and for adequate working space in HV pits:



Figure 1 shows cable entry details where cable bends need to be accommodated within the HV pit:

Figure 1 - Plan of Cable Entry

Figure 2 shows details of the pit indicating the minimum height of the conduit above the floor of the pit.

Figure 2 - Section through Pit

Reference should be made to Ausgrid approved jointing instructions for information on cable joint space requirements. Where cable joints are made in a pit, the length of straight cable required to assemble the joint shall also be considered, this shall include the parking of the joint components during the joint assembly process.

The location of the cables and joints should be positioned such that it does not hinder personnel accessing the pit or place the exposed cable joint or cable at risk of damage. Placing any pressure or load on exposed cable joint and or cable is not permitted. This includes stepping onto or using the cable joint or cable for support whilst accessing or working within the pit.

6.4.4 Columns Columns can interfere with cable pulling and jointing, and therefore shall be avoided where possible. The use of roof beams or thicker roof slabs is preferred.

Where the use of columns is unavoidable, the location of the column within the pit is to be approved by the Project Officer.



6.4.5 Access and egress An absolute minimum of two pit accesses shall be provided.

Additional accesses may be needed to comply with the criteria below:

• All accesses shall be suitable for personnel entry, egress, ventilation and cable pulling.

• All accesses shall be 900mm x 900mm size.

• Accesses shall be located in corners of the pit where possible.

• Accesses shall be located away from cable alignments and ductline entries.

• Where the pit is located such that it crosses opposing lanes of traffic, the pit shall have two accesses in each lane so that safe access (two accesses open) is possible by closing one traffic direction only.

• If the pit is effectively divided into sections by walls, cable banks or split levels, every section of the pit shall have a minimum of two accesses.

• The distance from anywhere in the pit to the nearest ladder base shall be 3m maximum, wherever this is reasonably practicable. Longer egress distances shall be assessed in accordance with Table 3.

• The ground adjacent to each access shall have a minimum of 600mm clear space to allow for positioning of portable fall-arrest rescue davit systems.

• Access covers shall be located and oriented so they open into an area free of obstructions.

Note that these requirements will normally result in a requirement for four accesses for pits larger than approximately 4m x 4m.

6.4.6 Multi-part accesses Multi-part accesses may be used for LV pits with the following limitations:

• Footpath locations only.

• Minimum clear opening of 900mm.

• Only to be used for pits of 2.2m x 2.2m and smaller.

Access covers with the following arrangements of covers are acceptable:

• 2 x 2 multi-part.

• 1 x 3 trench covers.

There shall be adequate space to allow removal and temporary storage of the covers and for pedestrian traffic around the pit, i.e. a minimum available footpath width of 1200mm on one side of the opening with the covers removed.

The support beam for a multi-part access cover shall be corrosion resistant. For non-corrosive environments, the support beam may be made from galvanised steel with a minimum galvanising rate of 600g/m². In corrosive environments 316 grade stainless steel is required.

6.4.7 Egress distance vs internal height Table 3 provides a matrix of cable pit design limits. The Table balances likely combinations of egress distances and internal heights for pits, and indicates the degree of acceptability for different design solutions:



Table 3 – Egress Distance vs Internal Height

Design solutions indicated as "Ideal" shall be adopted where reasonably practicable.

Design solutions indicated as "Accepted occasionally" and "Examples are available" may be approved by Ausgrid via a NS181 Network Standard Variation Request only where:

• Site constraints prevent the "Ideal" solution, and;

• There are no future Ausgrid plans to increase the number of feeders that will pass through the pit, and;

• Pit congestion is not excessive, and;

• Egress distance is as short as is reasonably practicable.

Design solutions indicated as "Marginal" or "Very Marginal" may be potentially acceptable, subject to detailed site-specific risk assessment, life-cycle cost analysis and Ausgrid approval via a NS181 Network Standard Variation Request.

Design solutions indicated as "Unacceptable" will not be accepted by Ausgrid.

6.4.8 Restricted access Restricted entry/egress design solutions may be acceptable for pit modifications that involve unavoidable site constraints such as existing cables/ductlines that prevent normal entry and egress via ladder. In these situations the following requirements shall apply:

• An absolute minimum of two unrestricted accesses shall be provided, and;

• Restricted entry/egress accesses shall be noted on pit signage, design drawings and in Ausgrid's GIS system, and;



• A risk assessment shall be carried out, and;

• Mitigation measures for emergency entry/egress (eg step irons) shall be considered, and

• An NS181 Network Standard Variation Request shall be submitted for Ausgrid consideration.

6.5 Confined space requirements All pits will normally be considered a confined space.

Pit designers shall be trained as per the requirements of the SafeWork NSW Confined Spaces Code of Practice.

In addition to any other requirements, the design of a pit will take into consideration the following:

• Risk assessment procedures.

• Risk control measures.

• Access & egress.

• Emergency procedures.

• Selection, use, fitting and maintenance of safety equipment.

The design of the pit shall aim to minimise the Complexity level (Levels 1-5) as described in Ausgrid's Confined Space Policy.

The designer shall supply the required Space Characteristics (in Resting State) criteria as defined in Ausgrid's Confined Space Field Sheet - Risk Assessment & Data Collection. These parameters will be used in the Confined Spaces register to determine training, rescue & working arrangements for future activities in the pit.

6.6 Standard items 6.6.1 General The following standard features are required for all pits:

• Access covers.

• Standard Ausgrid ladders (Drawings 49813 or 157908).

• Retractable handrails (Drawing 120488).

• Pulling eyes (Drawing 63678).

In addition the following features are required for some pits:

• Drainage sump (300mm x 300mm x 300mm deep) with hinged cover (Gatic 331S33L hinged grate and frame or equivalent) adjacent to the base of certain access ladders, required for all pits apart from pre-cast reinforced concrete pits.

• Falls in the base slab towards the sumps to provide drainage, required for all pits apart from pre-cast reinforced concrete pits.

• Temporary road plate and beam system, if needed for covering the pit during construction.

• Cable supports are required for HV narrow pits.

• Embedded earthing is required for 33kV & 132kV pits.

The design drawings shall indicate the features provided in the pit, and the drawing title shall include the size of the pit.

Ausgrid standard drawings may be obtained from the Project Officer.



6.6.2 Access covers Pit access covers shall comply with AS 3996. As a minimum, Class D watertight units are required for roads and Class C watertight units are required for footpath situations. Covers shall be tested in accordance with AS 3996 and test certificates made available on application. In addition, covers shall sustain a modified type test, using the ultimate limit state design load, without fracture: a) The test load shall be applied, without shock, five times, sustaining the test load and zero load

alternately for minimum periods of 30 seconds b) Any resultant permanent set measured along the unit's long axis shall, after removal of the test

load, be not greater than 0.8% of the dear opening span. c) Test certificates shall be made available on application.

If the proposed covers do not comply with these test requirements the next higher load classification may be used (ie Class E or D respectively), subject to Ausgrid approval via a NS181 Network Standard Variation Request. Covers shall be made from ductile iron as per AS 3996 2.2(b) with concrete infill for roads and concrete or paver infill for footpath situations, unless approved otherwise by the Project Officer. Concrete infill covers should preferably be filled with concrete by the cover manufacturer rather than filled on site, to reduce the risk of quality problems. Covers in road carriageways shall include black pigment in the concrete (and preferably, similar light reflective characteristics to the road top coat) to match the road surface. Covers that accommodate paver infill are acceptable provided the edge of the frame and the cover are each a minimum of 5mm thick with the cast elements extending to the surface of the paving. Covers for use with pavers are to have a 60mm set down to match the pavers. Covers that utilise edge plates attached to the cast lid to enclose infill paving and as the interface between the cover and the frame are not acceptable. The cover shall not present a trip hazard or a hazard to bicycles or motor bikes. Surfaces of smooth steel that may become slippery are not acceptable. The life of the access cover shall be considered including its corrosion performance and its wear under traffic loads. Pit access cover lifting keyholes shall be provided as per AS 3996 3.2.2.6. The lifting keyhole dimensions in AS 3996 Figure 3.1 and the 35mm (+5, -0mm) distance from the edge of a cover to the centre of a lifting keyhole shall be mandatory rather than "preferred". For security, standard purpose-made keys or lifting devices shall be used to ensure access to the pits is limited. The covers shall be designed so that the following keys may be used to open them: a) Long handle Gatic type key (Ausgrid stockcode 216). b) Short handle Gatic type key (Ausgrid stockcode 232).

• Permanent marking to AS 3996 1.6 shall not be provided, as this could pose a slip/trip hazard

and would become detached with time.

• Covers in road carriageways shall be installed to be opened in the direction of the traffic lane (ie not across the lanes) and shall open in the opposite direction to the flow of traffic.

• The design of the access cover, frame and roof slab shall allow for reasonable ease of modification to provide for future possible changes in road/footpath levels. The roof slab shall have a minimum cover depth of 200mm in footpaths, and 450mm in the roadway.

• Covers and frames shall be installed in accordance with the manufacturer’s installation instructions.



6.6.3 Ladders Vertical twin-stile rung-type ladders shall be provided in accordance with AS 1657. This ladder type provides good lifting access, maximises internal pit clearances, and is compatible with Ausgrid's normal fall arrest system.

Vertical single-stile ladders shall not be allowed due to general unsuitability for confined space usage.

Ausgrid drawing 49813 details the standard vertical ladder and drawing 120488 details the retractable handrails.

Note: These designs are only appropriate for pits of 1800mm minimum depth. For shallower pits, access complying with AS 1657 shall be provided.

6.6.4 Pulling eyes The Project Officer shall approve the proposed pulling eye locations prior to the construction of the pit.

Galvanised pulling eyes are required in the walls or floor of the pit, these shall be Type A, C or D (preferred) as shown in drawing 63678 with a minimum Safe Working Load of 50kN. Type D anchors shall meet the "lifting insert" requirements of AS3850.1.

For selected straight through LV pits, a reduced pulling eye rating of 15kN Safe Working Load may be acceptable, subject to a risk assessment and Ausgrid approval via a NS181 Network Standard Variation Request.

The exact location of pulling eyes is to be determined when the locations of the incoming cable ducts are known. Pulling eyes are to be positioned such that they are in line with the cable ducts wherever possible.

Figure 3 is indicative of typical pulling eye locations. Where a duct line has more than one conduit, multiple pulling eyes may be required.

Figure 3 - Typical pulling eye locations

6.6.5 Cable supports Pit designs for HV narrow pits shall include provision to support the planned number of cables via the use of cable support brackets along the side walls of the pit. The support brackets (or provision for future brackets) shall be designed to permit the installation of a straight-through joint for each feeder.



Cable support brackets shall be designed to support the heaviest size of power cable likely to be installed in the pit. Provision for copper pilot or optical fibre cables shall also be provided, with any optical pilots arranged in accordance with the relevant requirements of NS203 and NS204.2.1.

6.6.6 Embedded earthing For 33kV and 132kV cable pits there shall be a requirement to install embedded earthing, refer to NS168 Specification for the Design and Construction of 33kV, 66kV and 132kV Underground Cables and NS260 Sub-Transmission Feeder Earthing Design.

Embedded earthing is constructed from the reinforced steel in the concrete slab and walls which is welded together to form a continuous conductive mesh. Connection points are then welded to the mesh to allow it to be bonded to the local earthing system.

Refer to standard drawings 212446 Sheet 1 for 33kV and Sheet 2 for 132kV.

Where embedded earthing is required the Project Officer will provide detailed earthing drawings showing the required construction, welding and connection details.

6.7 Design drawings Ausgrid requires copies of any drawing produced in relation to the construction of any pit that is to be included as part of Ausgrid’s network assets. Refer also to NS149 Drawing Content for Chamber Type Substations, Control Points, Cable Risers and Ductlines.

Structural drawings of the proposed pit, certified by a Structural Engineer, are to be submitted to the Project Officer for approval. Construction shall not commence without an approved drawing. The drawing shall include all necessary provisions from this Standard and shall be fully dimensioned.

The structural drawings are to be presented to the Project Officer as full sized or electronic form drawings. All drawings are to be placed on drawing sheets, in sizes A0, A1, A2, A3, A4 or B1 only, in accordance with ISO-A and ISO-B standard.

Each sheet shall utilise a drawing border and drawings are to comply with the latest edition of the AS 1100 series. Electronic drawings are to be compatible with the latest release of AutoCAD or Microstation software.

The Project Officer will advise on which of these systems will be acceptable for the project.

The title block of each sheet shall contain the following information:

• The pit number and description of the pit, so that the Project Officer can readily identify where the pit design is to be used.

• The geographic location of the pit.

• The size of the pit.

• The material used: pre-cast, blockwork etc.

• The drawing number and the amendment or revision or issue number assigned by the designer

• The date of original design and subsequent amendments, revisions or issues

• The printed name and signature of the responsible accredited designer

The drawing sheets shall also have provision for:

• The addition of Ausgrid’s drawing number. This number will be added by Ausgrid once the pit design or variation to the design is accepted by the Project Officer. A blank rectangular space



of 90mm wide x 50mm high is to be left immediately above the title block for the addition of this number.

• An amendment or revision or issue table.

The drawings must not bear Ausgrid’s name or logo if an accredited designer other than Ausgrid has undertaken the design.

The structural pit drawings shall be fully dimensioned and contain cross-references to other drawings in the project. All dimensions shall be to clear and finished sizes and sufficient details shall be present to fully define the pits to be constructed in accordance with the design. Drawings made over grid or modular base lines without sufficient dimensions are not satisfactory.

The drawings shall provide all construction details and shall also document the design loads and design life.

7.0 IDENTIFICATION AND SIGNAGE 7.1 Summary

Signage requirements are summarised in Table 4 below:

Table 4 – Signage Requirements

Sign Classification Location

Pit identification Information One sign per pit at the access that is likely to be the most commonly used.

Fall arrest Mandatory At every access, for pits where fall arrest procedures are to be employed.

Confined space Danger At every access.

Webbing Danger Directly under every access.

Sump trip hazard Warning Sign on nearest wall at 1m height.

Load capacity of pulling eyes

Information Wall-mounted pulling eyes - sign adjacent to each Type A & C pulling eye. No signs are required for Type D since foot anchors are stamped with their load rating as per AS3850.1. Floor-mounted pulling eyes - sign on nearest wall at 1m height for each Type A & C pulling eye. No signs are required for Type D since foot anchors are stamped with their load rating as per AS3850.1.

Signs that are classified as mandatory, danger and warning signs shall meet the requirements of AS1319. The confined space danger sign and webbing danger sign shall also meet the requirements of AS2865.

All signage shall be corrosion resistant and shall be fixed with corrosion resistant fasteners.

The pit identification sign shall include design information including pit number, drawing number, design company and construction year. The pit identification sign shall be made from 3mm thick aluminium plate and shall have smoothed and rounded edges and corners. Pits are to be numbered in accordance with the requirements of NS148 Overhead Line Support, Street Light Column, Pit and Pillar Numbering. On completion, the number of the drawing that was used to construct the pit and survey information of the pits location is to be given to the Project Officer who will forward details to the GIS section.



Webbing danger signs and installation instructions shall be provided by the Project Officer.

7.2 Typical signs

Figure 4 – fall arrest sign

Figure 5 – confined space sign



Figure 6 – webbing sign, as installed

Figure 7 – sump trip hazard sign



8.0 INSPECTIONS 8.1 General

To ensure the pit meets all Ausgrid requirements and relevant design criteria, Ausgrid shall be given the opportunity to perform inspections as described in this section.

In addition, during construction the Certifying Engineer shall carry out all inspections deemed necessary in order to provide the required certification.

Drawings indicating Ausgrid approval shall be used for construction and shall be made available to the Compliance Officer.

8.2 Ground conditions During the excavation of the pit, the Certifying Engineer is to inspect the excavation to ensure the ground conditions are suitable for the proposed design. Where there are deviations from the design assumptions, amended drawings to allow for the deviations shall be produced and submitted for Ausgrid approval.

Where Acid Sulfate Soils (ASS) are present, the pit design must allow for these conditions. As the impact of ASS will affect the design of the pit, the contractor is responsible for identifying soil types. The Project Officer shall be supplied with test certificates relating to soil types prior to acceptance of the design.

8.3 Reinforcement inspections Inspection and Test Plans are required to be submitted by the contractor to verify that the construction has been carried out in accordance with the specification.

A Professional Structural Engineer who is approved by the Project Officer will carry out inspections of reinforcement. In addition the Compliance Officer will inspect the reinforcement and shall be given a minimum of 24 hour notice of any opportunity for inspection.

In all cases, the Professional Structural Engineer is required to certify that all reinforcement has been installed in accordance with the approved specific pit structural design.

Where embedded earthing has been installed the Compliance Officer may inspect the welding, the connection points and carry out an electrical continuity test from a number of points on the mesh to the connection points to verify that the construction has been carried out in accordance with the specification.

8.4 Concrete pours The Compliance Officer shall be given the opportunity to witness all concrete pours and where appropriate make comments or reject the work if it does not comply with relevant standards.

8.5 Final inspection The Compliance Officer will inspect the completed pit prior to the issue of the Certificate of Practical Completion.

Pit ladders, sump grates, pulling eyes and signage etc, are to be installed and any material such as formwork and the like to be removed from the pit.

9.0 CERTIFICATION The following documentation shall be provided:

a. Structural Certificate certifying the design and construction of the pit to the relevant Australian Standards, signed by a Professional Structural Engineer. The Professional Structural Engineer shall be eligible for registration with the Institution of Engineers (Australia) under classification NPER3.



b. Certificate certifying that the WHS and Confined Space aspects of the design of the pit are fit for purpose.

c. Evidence of the Certifying Engineer's professional indemnity insurance cover.

d. Details of the training and experience, including WHS & Confined Spaces, of the designer and Certifier shall be included with the certificate.

e. Safety In Design report.

f. Confined Space Field Sheet - Risk Assessment & Data Collection.

10.0 COMPLETION The Compliance Officer will issue a Certificate of Practical Completion when the requirements of Sections 7.0 to 9.0 have been met.



11.0 RECORDKEEPING The table below identifies the types of records relating to the process, their storage location and retention period.

Table 5 – Recordkeeping

Type of Record Storage Location Retention Period*

Approved copy of the network standard

BMS Network sub process Standard – Company

Unlimited

Draft Copies of the network standard during amendment/creation

HPRM Work Folder for Network Standards (HPRM ref. 2014/21250/273)

Unlimited

Working documents (emails, memos, impact assessment reports, etc.)

HPRM Work Folder for Network Standards (HPRM ref. 2014/21250/273)

Unlimited

* The following retention periods are subject to change e.g. if the records are required for legal matters or legislative changes. Before disposal, retention periods should be checked and authorised by the Records Manager.

12.0 AUTHORITIES AND RESPONSIBILITIES For this network standard the authorities and responsibilities of Ausgrid employees and managers in relation to content, management and document control of this network standard can be obtained from the Company Procedure (Network) – Production/Review of Network Standards. The responsibilities of persons for the design or construction work detailed in this network standard are identified throughout this standard in the context of the requirements to which they apply.

13.0 DOCUMENT CONTROL Content Coordinator : Manager - Transmission and Distribution Mains Engineering

Distribution Coordinator : Senior Engineer – Guidelines, Polices and Standards



Annexure A – Sample Compliance Checklist